Networks route voice and data information around the world. Different types of networks are used for different types of environments and requirements and networks are often interconnected to provide internetwork communication. Three types of networks are the most common. A broadband or broadcast network covers a wide area. A metropolitan area network covers a smaller region. Local area networks are used in a limited distance environment such as an office or business.
As the telecommunications equipment that operates the network increases in sophistication and in complexity and capacity, and further, as the use of the networks increase and the number of the networks increase, the complexity of designing a network increases. The complexity of designing a network has resulted in the development of design tools to assist a network designer in designing a network. Typically a customer of a telecommunication equipment manufacturer or distributor will come to the telecommunication company with certain system requirements referred to as the customer's traffic demand for the network. The network designer develops a network of equipment having certain capabilities and features to be located at predetermined locations to form a network which meets the customer's requirements. The capability of the network designer may reflect on the cost of setting up and operating the network. A well designed network may be cheaper to purchase as well as cheaper to operate. Furthermore, proper specification of the network will also minimize the frequency of failed connections during routing while maximizing use of the network. The design of telecommunication networks is a science in itself and several books have been written on the subject including, Roshan L. Sharma, Network Topology Optimization, the Art and Science of Network Design (van Nostrand Reinholt, 1990). See also, Andrew S. Tanenbaum, Computer Networks, Second Edition (Prentice-Hall 1989).
It is apparent that as the technology of the telecommunication equipment changes, so do the rules for designing an optimum network. In particular telecommunications manufacturer StrataCom, Inc. of San Jose, Calif., has developed network communications modules, referred to as IPX.TM. modules (IPX is trademark of StrataCom, Inc.) that groups point to point connections referred to as "virtual circuits," having like characteristics. These groups of virtual circuits are referred to as "virtual paths." The virtual paths increase the capacity of the node from 256 to 1,024 virtual circuits. The nodes having the virtual path capability can group a predetermined number of virtual circuits into virtual paths, up to the maximum number of virtual paths of the node. By increasing the virtual circuit capacity at each node, the number of nodes required in the network is dramatically decreased.
The network optimization and design tools available, however, do not provide for grouping of virtual circuits into virtual paths and therefore, any network topology generated from using these design tools will not be optimized. In particular, existing network topology design techniques provide for single routed virtual paths through the nodes. Therefore, a network designed using these techniques will over-specify the amount of equipment required. Furthermore, there is no apparent way to simply decrease the amount of equipment and nodes required because the design not only specifies the amount of equipment but also the location the equipment will be placed.